[clang-tidy] Migrate UseAuto from clang-modernize to clang-tidy.
http://reviews.llvm.org/D12231
llvm-svn: 245703
diff --git a/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.cpp
new file mode 100644
index 0000000..b688f10
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/modernize/UseAutoCheck.cpp
@@ -0,0 +1,368 @@
+//===--- UseAutoCheck.cpp - clang-tidy-------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "UseAutoCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang;
+using namespace clang::ast_matchers;
+using namespace clang::ast_matchers::internal;
+
+namespace clang {
+namespace tidy {
+namespace modernize {
+namespace {
+
+const char IteratorDeclStmtId[] = "iterator_decl";
+const char DeclWithNewId[] = "decl_new";
+
+/// \brief Matches variable declarations that have explicit initializers that
+/// are not initializer lists.
+///
+/// Given
+/// \code
+/// iterator I = Container.begin();
+/// MyType A(42);
+/// MyType B{2};
+/// MyType C;
+/// \endcode
+///
+/// varDecl(hasWrittenNonListInitializer()) maches \c I and \c A but not \c B
+/// or \c C.
+AST_MATCHER(VarDecl, hasWrittenNonListInitializer) {
+ const Expr *Init = Node.getAnyInitializer();
+ if (!Init)
+ return false;
+
+ // The following test is based on DeclPrinter::VisitVarDecl() to find if an
+ // initializer is implicit or not.
+ if (const auto *Construct = dyn_cast<CXXConstructExpr>(Init)) {
+ return !Construct->isListInitialization() && Construct->getNumArgs() > 0 &&
+ !Construct->getArg(0)->isDefaultArgument();
+ }
+ return Node.getInitStyle() != VarDecl::ListInit;
+}
+
+/// \brief Matches QualTypes that are type sugar for QualTypes that match \c
+/// SugarMatcher.
+///
+/// Given
+/// \code
+/// class C {};
+/// typedef C my_type;
+/// typedef my_type my_other_type;
+/// \endcode
+///
+/// qualType(isSugarFor(recordType(hasDeclaration(namedDecl(hasName("C"))))))
+/// matches \c my_type and \c my_other_type.
+AST_MATCHER_P(QualType, isSugarFor, Matcher<QualType>, SugarMatcher) {
+ QualType QT = Node;
+ while (true) {
+ if (SugarMatcher.matches(QT, Finder, Builder))
+ return true;
+
+ QualType NewQT = QT.getSingleStepDesugaredType(Finder->getASTContext());
+ if (NewQT == QT)
+ return false;
+ QT = NewQT;
+ }
+}
+
+/// \brief Matches named declarations that have one of the standard iterator
+/// names: iterator, reverse_iterator, const_iterator, const_reverse_iterator.
+///
+/// Given
+/// \code
+/// iterator I;
+/// const_iterator CI;
+/// \endcode
+///
+/// namedDecl(hasStdIteratorName()) matches \c I and \c CI.
+AST_MATCHER(NamedDecl, hasStdIteratorName) {
+ static const char *IteratorNames[] = {"iterator", "reverse_iterator",
+ "const_iterator",
+ "const_reverse_iterator"};
+
+ for (const char *Name : IteratorNames) {
+ if (hasName(Name).matches(Node, Finder, Builder))
+ return true;
+ }
+ return false;
+}
+
+/// \brief Matches named declarations that have one of the standard container
+/// names.
+///
+/// Given
+/// \code
+/// class vector {};
+/// class forward_list {};
+/// class my_ver{};
+/// \endcode
+///
+/// recordDecl(hasStdContainerName()) matches \c vector and \c forward_list
+/// but not \c my_vec.
+AST_MATCHER(NamedDecl, hasStdContainerName) {
+ static const char *ContainerNames[] = {"array", "deque",
+ "forward_list", "list",
+ "vector",
+
+ "map", "multimap",
+ "set", "multiset",
+
+ "unordered_map", "unordered_multimap",
+ "unordered_set", "unordered_multiset",
+
+ "queue", "priority_queue",
+ "stack"};
+
+ for (const char *Name : ContainerNames) {
+ if (hasName(Name).matches(Node, Finder, Builder))
+ return true;
+ }
+ return false;
+}
+
+/// Matches declarations whose declaration context is the C++ standard library
+/// namespace std.
+///
+/// Note that inline namespaces are silently ignored during the lookup since
+/// both libstdc++ and libc++ are known to use them for versioning purposes.
+///
+/// Given:
+/// \code
+/// namespace ns {
+/// struct my_type {};
+/// using namespace std;
+/// }
+///
+/// using std::vector;
+/// using ns:my_type;
+/// using ns::list;
+/// \code
+///
+/// usingDecl(hasAnyUsingShadowDecl(hasTargetDecl(isFromStdNamespace())))
+/// matches "using std::vector" and "using ns::list".
+AST_MATCHER(Decl, isFromStdNamespace) {
+ const DeclContext *D = Node.getDeclContext();
+
+ while (D->isInlineNamespace())
+ D = D->getParent();
+
+ if (!D->isNamespace() || !D->getParent()->isTranslationUnit())
+ return false;
+
+ const IdentifierInfo *Info = cast<NamespaceDecl>(D)->getIdentifier();
+
+ return (Info && Info->isStr("std"));
+}
+
+/// \brief Returns a DeclarationMatcher that matches standard iterators nested
+/// inside records with a standard container name.
+DeclarationMatcher standardIterator() {
+ return allOf(
+ namedDecl(hasStdIteratorName()),
+ hasDeclContext(recordDecl(hasStdContainerName(), isFromStdNamespace())));
+}
+
+/// \brief Returns a TypeMatcher that matches typedefs for standard iterators
+/// inside records with a standard container name.
+TypeMatcher typedefIterator() {
+ return typedefType(hasDeclaration(standardIterator()));
+}
+
+/// \brief Returns a TypeMatcher that matches records named for standard
+/// iterators nested inside records named for standard containers.
+TypeMatcher nestedIterator() {
+ return recordType(hasDeclaration(standardIterator()));
+}
+
+/// \brief Returns a TypeMatcher that matches types declared with using
+/// declarations and which name standard iterators for standard containers.
+TypeMatcher iteratorFromUsingDeclaration() {
+ auto HasIteratorDecl = hasDeclaration(namedDecl(hasStdIteratorName()));
+ // Types resulting from using declarations are represented by elaboratedType.
+ return elaboratedType(allOf(
+ // Unwrap the nested name specifier to test for one of the standard
+ // containers.
+ hasQualifier(specifiesType(templateSpecializationType(hasDeclaration(
+ namedDecl(hasStdContainerName(), isFromStdNamespace()))))),
+ // the named type is what comes after the final '::' in the type. It
+ // should name one of the standard iterator names.
+ namesType(
+ anyOf(typedefType(HasIteratorDecl), recordType(HasIteratorDecl)))));
+}
+
+/// \brief This matcher returns declaration statements that contain variable
+/// declarations with written non-list initializer for standard iterators.
+StatementMatcher makeIteratorDeclMatcher() {
+ return declStmt(
+ // At least one varDecl should be a child of the declStmt to ensure
+ // it's a declaration list and avoid matching other declarations,
+ // e.g. using directives.
+ has(varDecl()),
+ unless(has(varDecl(anyOf(
+ unless(hasWrittenNonListInitializer()), hasType(autoType()),
+ unless(hasType(
+ isSugarFor(anyOf(typedefIterator(), nestedIterator(),
+ iteratorFromUsingDeclaration())))))))))
+ .bind(IteratorDeclStmtId);
+}
+
+StatementMatcher makeDeclWithNewMatcher() {
+ return declStmt(has(varDecl()),
+ unless(has(varDecl(anyOf(
+ unless(hasInitializer(ignoringParenImpCasts(newExpr()))),
+ // FIXME: TypeLoc information is not reliable where CV
+ // qualifiers are concerned so these types can't be
+ // handled for now.
+ hasType(pointerType(
+ pointee(hasCanonicalType(hasLocalQualifiers())))),
+
+ // FIXME: Handle function pointers. For now we ignore them
+ // because the replacement replaces the entire type
+ // specifier source range which includes the identifier.
+ hasType(pointsTo(
+ pointsTo(parenType(innerType(functionType()))))))))))
+ .bind(DeclWithNewId);
+}
+
+} // namespace
+
+void UseAutoCheck::registerMatchers(MatchFinder *Finder) {
+ Finder->addMatcher(makeIteratorDeclMatcher(), this);
+ Finder->addMatcher(makeDeclWithNewMatcher(), this);
+}
+
+void UseAutoCheck::replaceIterators(const DeclStmt *D, ASTContext *Context) {
+ for (const auto *Dec : D->decls()) {
+ const auto *V = cast<VarDecl>(Dec);
+ const Expr *ExprInit = V->getInit();
+
+ // Skip expressions with cleanups from the intializer expression.
+ if (const auto *E = dyn_cast<ExprWithCleanups>(ExprInit))
+ ExprInit = E->getSubExpr();
+
+ const auto *Construct = dyn_cast<CXXConstructExpr>(ExprInit);
+ if (!Construct)
+ continue;
+
+ // Ensure that the constructor receives a single argument.
+ if (Construct->getNumArgs() != 1)
+ return;
+
+ // Drill down to the as-written initializer.
+ const Expr *E = (*Construct->arg_begin())->IgnoreParenImpCasts();
+ if (E != E->IgnoreConversionOperator()) {
+ // We hit a conversion operator. Early-out now as they imply an implicit
+ // conversion from a different type. Could also mean an explicit
+ // conversion from the same type but that's pretty rare.
+ return;
+ }
+
+ if (const auto *NestedConstruct = dyn_cast<CXXConstructExpr>(E)) {
+ // If we ran into an implicit conversion contructor, can't convert.
+ //
+ // FIXME: The following only checks if the constructor can be used
+ // implicitly, not if it actually was. Cases where the converting
+ // constructor was used explicitly won't get converted.
+ if (NestedConstruct->getConstructor()->isConvertingConstructor(false))
+ return;
+ }
+ if (!Context->hasSameType(V->getType(), E->getType()))
+ return;
+ }
+
+ // Get the type location using the first declaration.
+ const auto *V = cast<VarDecl>(*D->decl_begin());
+
+ // WARNING: TypeLoc::getSourceRange() will include the identifier for things
+ // like function pointers. Not a concern since this action only works with
+ // iterators but something to keep in mind in the future.
+
+ SourceRange Range(V->getTypeSourceInfo()->getTypeLoc().getSourceRange());
+ diag(Range.getBegin(), "use auto when declaring iterators")
+ << FixItHint::CreateReplacement(Range, "auto");
+}
+
+void UseAutoCheck::replaceNew(const DeclStmt *D, ASTContext *Context) {
+ const auto *FirstDecl = cast<VarDecl>(*D->decl_begin());
+ // Ensure that there is at least one VarDecl within the DeclStmt.
+ if (!FirstDecl)
+ return;
+
+ const QualType FirstDeclType = FirstDecl->getType().getCanonicalType();
+
+ std::vector<SourceLocation> StarLocations;
+ for (const auto *Dec : D->decls()) {
+ const auto *V = cast<VarDecl>(Dec);
+ // Ensure that every DeclStmt child is a VarDecl.
+ if (!V)
+ return;
+
+ const auto *NewExpr = cast<CXXNewExpr>(V->getInit()->IgnoreParenImpCasts());
+ // Ensure that every VarDecl has a CXXNewExpr initializer.
+ if (!NewExpr)
+ return;
+
+ // If VarDecl and Initializer have mismatching unqualified types.
+ if (!Context->hasSameUnqualifiedType(V->getType(), NewExpr->getType()))
+ return;
+
+ // Remove explicitly written '*' from declarations where there's more than
+ // one declaration in the declaration list.
+ if (Dec == *D->decl_begin())
+ continue;
+
+ // All subsequent declarations should match the same non-decorated type.
+ if (FirstDeclType != V->getType().getCanonicalType())
+ return;
+
+ auto Q = V->getTypeSourceInfo()->getTypeLoc().getAs<PointerTypeLoc>();
+ while (!Q.isNull()) {
+ StarLocations.push_back(Q.getStarLoc());
+ Q = Q.getNextTypeLoc().getAs<PointerTypeLoc>();
+ }
+ }
+
+ // FIXME: There is, however, one case we can address: when the VarDecl pointee
+ // is the same as the initializer, just more CV-qualified. However, TypeLoc
+ // information is not reliable where CV qualifiers are concerned so we can't
+ // do anything about this case for now.
+ SourceRange Range(
+ FirstDecl->getTypeSourceInfo()->getTypeLoc().getSourceRange());
+ auto Diag = diag(Range.getBegin(), "use auto when initializing with new"
+ " to avoid duplicating the type name");
+
+ // Space after 'auto' to handle cases where the '*' in the pointer type is
+ // next to the identifier. This avoids changing 'int *p' into 'autop'.
+ Diag << FixItHint::CreateReplacement(Range, "auto ");
+
+ // Remove '*' from declarations using the saved star locations.
+ for (const auto &Loc : StarLocations) {
+ Diag << FixItHint::CreateReplacement(Loc, "");
+ }
+}
+
+void UseAutoCheck::check(const MatchFinder::MatchResult &Result) {
+ if (const auto *Decl = Result.Nodes.getNodeAs<DeclStmt>(IteratorDeclStmtId)) {
+ replaceIterators(Decl, Result.Context);
+ } else if (const auto *Decl =
+ Result.Nodes.getNodeAs<DeclStmt>(DeclWithNewId)) {
+ replaceNew(Decl, Result.Context);
+ } else {
+ llvm_unreachable("Bad Callback. No node provided.");
+ }
+}
+
+} // namespace modernize
+} // namespace tidy
+} // namespace clang